1. Field of the Invention
This invention relates to a device for injecting a fluid or inserting an object beneath the skin of an animal.
2. Prior Art
There are a number of devices available for injecting livestock, for instance with a vitamin solution or other medication, but these suffer from a number of disadvantages.
The simplest device is a hand-held syringe. There are also hand-held injection guns which have a needle for inserting into an animal and a lever or trigger mechanism which is squeezed to inject fluid into the animal. With these devices, it is necessary to get close to the animal to be injected, to push the needle into the animal and then depress the plunger /r squeeze the trigger to inject the animal. In practice, these devices are difficult to use with un-restrained livestock, since the animals tend to move away and a certain degree of skill is required to carry out quickly the two actions of inserting the needle and then depressing the plunger (or squeezing the trigger) to inject the animal. Often the animal may move when the needle is inserted before the plunger can be depressed, or the animal moves before the needle is inserted and fluid is wasted as the plunger is inadvertently depressed. There is also considerable danger that the operator will accidentally inject himself if he misses an animal as it moves past his legs.
A further type of arrangement is described in U.S. Pat. No. 3,809,083. This comprises a syringe carried on the end of a pole together with a spring-loaded mechanism. When the needle is jabbed into an animal the spring-loaded mechanism is automatically triggered to discharge the syringe. The spring-loaded mechanism is complicated and requires many moving parts and the device can be inconvenient to use, especially when the animal is close to the person operating the device.
Dart guns may also be used to fire a dart containing the required fluid into the animal. However, these require skill in aiming and hitting the chosen animal, are relatively slow when many animals have to be injected, and require expensive equipment and may require a gun licence to operate.
Other devices are available for tattooing or marking an animal. These comprise a tattoo head (made up of a plurality of small needles) or a stamp, mounted on the end of an arm or handle. This type of device can be swung onto or pushed against the skin of an animal to provide the required marking. These devices are, however, limited to surface marking and are unable to inject anything beneath the skin.